I think it may be "from the plowed fields" since it describes the word "eat"
There are some connotations for the word <em>'observe'</em> that can bring positive feelings to the person such as 'notice,' 'note,' 'honour,' 'appreciate,' 'abide by,' and even 'respect' when you pay attention to others. It is worth to mention that a connotation is the meaning of a word that is connected to the emotions and associations, which carry a positive feeling.
The technique makes both excerpts effective is an appeal to logic.
Logos is the logic, reasoning and argument, or simulation of it, in a persuasive appeal.
Logos is a persuasive technique that tries to persuade an audience using logical arguments and supporting evidence.
I agree with the person above - I believe the correct answer is A. serenity.
Thoreau was a transcendentalist, which means that he wrote about nature quite a lot. He believed that people should return to living in nature and escape from the concrete cities they were surrounded with in order to find their true selves once again. His description of the pond during the night and day creates a serene and peaceful picture one could relax to.